修复重复提交数据

@@ -118,7 +118,6 @@ class DedupService:
                     "insert into lyric_lines (lyric_id, role, line_no, normalized_line, line_hash) values (%s, %s, %s, %s, %s)",
                     line_rows,
                 )
-        conn.commit()
 
     def _recall_candidates(self, conn: Any, record: LyricRecord) -> list[LyricRecord]:
         """Three-tier recall: exact_hash → pg_trgm → line_hash."""